How do I make a "landmine"?

You will need a certain point that once someone heads to the location, an invisible creeper gets summoned. For this, you need 2 Always Active Repeating Command Blocks.

#1: Creeper Invisibility

effect @e[type=creeper] ~ ~ ~ invisibility 2 1 true

#2: Act of Explosion

execute @a[x=#,z=#,dx=0,dz=0] ~ ~ ~ summon creeper 

This will leave in a few invisible creepers if any survived. Make a redstone clock that should take a while before removing all creepers in the area.

The commands to be used:

#3: Creeper Extinction (Impulse Needs Redstone)

kill @e[type=creeper,x=#,z=#,dx=#,dz=#]

#4: Gunpowder Removal (To Destroy Any Remains of Creepers) (Impulse Needs Redstone / Always Active Conditional Chain)

kill @e[type=item,name=Gunpowder]

Notes:

• All # should be replaced with the numbers depending on the coordinates and distance of the explosion.

Instead of using just regular TNT or creepers, OR even just commands, use this:

1. Find flat land
2. Dig a 3x2x2 hole (3x, 2y, 2z, z and x can be swapped)
3. View from above:

|P|O|R|

|T|R|R|

• P = pufferfish
• T = tnt minecart on top of activator rails
• R = redstone
• O = observer face pointing left

4. Cover up! (Note: the blank space between the por and trr is not supposed to be there. Idk how to fix it.)